class HelloWorld{
	public static void main(String[] args){
		System.out.println("????");
	}
}


public class A{
   public static void main(String[] args){
		System.out.println("A类");
   }
}

class B{
   public static void main(String[] args){
		System.out.println("B??");
   }
}

class C{
   public static void main(String[] args){
		System.out.println("C??");
   }
}